Method of bending sheet metal to form three-dimensional structures

Abstract

A method for bending sheet metal includes introducing to the sheet metal thinned regions which are positioned either along or immediately adjacent to a bending line. These thinned regions allow the metal to be easily bent along the bending line using conventional hand tools or non-specialized machines. The thinned regions may be shaped as slots having a specific width, length, end shape, spacing from each adjacent slot, and depth into the metal sheet. According to one embodiment of the invention, each slot is cut through the entire thickness of the metal sheet. Other related embodiments require that the slots be only partially cut or etched thereby having a depth that is less than the thickness of the metal sheet. The thinned regions may be any appropriate shape as controlled by the shape of the bend, the type of metal, the thickness of the metal, the ductility of the metal, the angle of the bend, and the application of the metal (e.g., load bearing, etc). According to a second embodiment, two generally parallel sets of thinned regions are formed adjacent and generally parallel to the bending line. In a preferred application, the two sets of thinned regions are slots (cutting through the metal) and are staggered or offset with respect to each other.

What is claimed is:  
     
       1. A method for bending two opposing sections of sheet metal of thickness T about an interposed bending line to form a 3-dimensional folded structure, said method comprising the steps of: 
       forming a plurality of elongated slots of length a and width b within said metal along said bending line, said elongated slots having at least one edge of major length that is generally parallel to said bending line, said slots being separated by a distance c along said bending line, said slots being formed by a cutting device of width k; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said plurality of slots encouraging said bending to occur along said bending line, wherein 
       a is not less than c but not greater than 30 times c,  
       b is not less than k but not greater than 2 times T,  
       c is not less than T/2 but not greater 3 times T, and wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines.  
     
     
       2. The method according to  claim 1 , wherein the forming step includes cutting entirely through said metal. 
     
     
       3. The method according to  claim 1 , wherein said cutting device is a laser cutter and where said width k equals the width of the laser beam. 
     
     
       4. The method according to  claim 1 , wherein said cutting device is a water jet cutter and where said width k equals the width of the water jet. 
     
     
       5. A method of bending two opposing sections of sheet metal of thickness T about an interposed bending line to form a 3-dimensional folded structure, said method comprising the steps of: 
       forming two rows of elongated slots within said metal, each said row comprising a plurality of said slots separated by a distance ‘e’ along said bending line, each said slot having a length ‘f’ and width ‘i’, and comprising an inner side wall located towards said bending line and an outer side wall located away from said bending line, each said slot is generally parallel to and spaced from said bending line such that the distance between two opposing said inner side wall equals j, said slots within one said row are staggered with respect to said slots within second said row by an offset distance g from either end of said slots, said slots including at least one edge of major length which is generally parallel to said bending line, said slots being formed by a cutting device of width k; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said plurality of slots encouraging said bending to occur along said bending line, wherein 
       f is greater than 4 times T,  
       i is not less than .k,  
       e equals f/2,  
       j is not less than T,  
       g is not less than T and not greater than 4 times T, and wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines.  
     
     
       6. The method according to  claim 5 , wherein said cutting device is a laser cutter and where said width k equals the width of the laser beam. 
     
     
       7. The method according to  claim 5 , wherein said cutting device is a water jet cutter and where said width k equals the width of the water jet. 
     
     
       8. A method for bending a plurality of opposing sections of sheet metal of thickness T about a corresponding plurality of interposed bending lines to form a 3-dimensional folded structure, said method comprising the steps of: 
       forming a plurality of elongated slots of length a and width b within said metal along said bending line, said elongated slots having at least one edge of major length that is generally parallel to said bending line, said slots being separated by a distance c along said bending line, said slots being formed by a cutting device of width ‘k’; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said plurality of slots encouraging said bending to occur along said bending line, wherein 
       a is not less than c but not greater than 30 times c,  
       b is not less than k but not greater than 2 times T,  
       c is not less than T/2 but not greater 3 times T, wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines, and wherein  
       said plurality of said bending lines is selected from a group comprising the following: 
       a configuration of parallel spaced lines,  
       a configuration of non-parallel spaced lines,  
       a configuration of lines that meet at one vertex,  
       a configuration of lines that meet at a plurality of vertices that define a tiling pattern,  
       a configuration of lines that meet at a plurality of vertices that fold into a polyhedron, and  
       a configuration of lines that fold into an origami figure.  
     
     
       9. The method according to  claim 8 , wherein said cutting device is a laser cutter and where width k equals the width of the laser beam. 
     
     
       10. The method according to  claim 8 , wherein said cutting device is a water jet cutter and where said width k equals the width of the water jet. 
     
     
       11. The method according to  claim 8 , wherein angles between two said opposing sections of said sheet metal are convex. 
     
     
       12. The method according to  claim 8 , wherein angles between two said opposing sections of said sheet metal are a combination of convex and concave angles. 
     
     
       13. A method for bending a plurality of opposing sections of sheet metal of thickness T about a corresponding plurality of interposed bending line to form a 3-dimensional folded structure, said method comprising the steps of: 
       forming two rows of elongated slots within said metal, each said row comprising a plurality of said slots separated by a distance e along said bending line, each said slot having a length f and width i, and comprising an inner side wall located towards said bending line an outer side wall located away from said bending line, each said slot is generally parallel to and spaced from said bending line such that the distance between two opposing said inner side wall equals j, said slots within one said row are staggered with respect to said slots within second said row by an offset distance g from either side of said slots, said slots including at least one edge of major length which is generally parallel to said bending line, said slots being formed by a cutting device of width k; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said plurality of slots encouraging said bending to occur along said bending line, wherein 
       f is greater than 4 times T,  
       i is not less than k,  
       e equals f/2,  
       j is not less than T,  
       g is not less than T and not greater than 4 times T, and wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines, wherein  
       said plurality of said bending lines is selected from a group comprising the following: 
       a configuration of parallel spaced lines,  
       a configuration of non-parallel spaced lines,  
       a configuration of lines that meet at one vertex,  
       a configuration of lines that meet at a plurality of vertices that define a tiling pattern,  
       a configuration of lines that meet at a plurality of vertices that fold into a polyhedron, and  
       a configuration of lines that fold into an origami figure.  
     
     
       14. The method according to  claim 13 , wherein said cutting device is a laser cutter and where said width k equals the width of the laser beam. 
     
     
       15. The method according to  claim 13 , wherein said cutting device is a water jet cutter and where said width k equals the width of the water jet. 
     
     
       16. The method according to  claim 13 , wherein angles between two said opposing sections of said sheet metal are convex. 
     
     
       17. The method according to  claim 13 , wherein angles between two said opposing sections of said sheet metal are a combination of convex and concave angles. 
     
     
       18. A method for bending two opposing sections of sheet metal of thickness T about an interposed bending line to form a 3-dimensional folded structure, said method comprising the steps of:: 
       forming a continuous thinned region within said metal along said bending line, said thinned region formed as a recess of predetermined sectional shape comprising two edges separated by predetermined width w along a surface of said sheet metal, two side walls of depth t across the thickness of said sheet, and a floor region, and said recess having at least one said edge that is generally parallel to said bending line, said recess being formed by a cutting device of width k; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said thinned region encouraging said bending to occur along said bending line, wherein 
       w is not less than k  
       t is not less that T/4 and not greater than {fraction (9/10)}ths of T, and wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines.  
     
     
       19. The method according to  claim 18 , wherein said side walls of said recess are parallel. 
     
     
       20. The method according to  claim 18 , wherein said side walls of said recess have a divergent angle. 
     
     
       21. The method according to  claim 18 , wherein said side walls of said recess have a stepped section. 
     
     
       22. The method according to  claim 18 , wherein said recess has a generally V-shaped section. 
     
     
       23. The method according to  claim 18 , wherein said recess has a generally rectangular section. 
     
     
       24. The method according to  claim 18 , wherein said floor plane of said recess is curved. 
     
     
       25. The method according to  claim 18 , wherein said cutting device is a water jet cutter and where k is the width of the water jet. 
     
     
       26. A method for bending a plurality of opposing sections of sheet metal of thickness T about a corresponding plurality of interposed bending lines to form a 3-dimensional folded structure, said method comprising the steps of: 
       forming plurality of continuous thinned regions within said metal along said bending lines, said thinned regions formed as a recess of predetermined sectional shape comprising two edges separated by a predetermined width w along a surface of said sheet metal, two side walls of depth t across the thickness of said sheet, and a floor region, and said recess having at least one said edge that is generally parallel to said bending line, said recess is formed by a cutting device of width k; and  
       bending said two opposing sections of metal sheet about said bending line,  
       said thinned region encouraging said bending to occur along said bending line, wherein 
       w is not less than k,  
       t is not less than T/4 and not greater than {fraction (9/10)}ths of T, and wherein  
       said bending line is selected from a group comprising the following: 
       a straight line,  
       a line curved in one direction,  
       a line curved in two directions and having at least one S-shaped line segment,  
       an irregular curved line, and  
       a combination of straight and curved lines, and wherein  
       said plurality of said bending lines is selected from a group comprising the following: 
       a configuration of parallel spaced lines,  
       a configuration of non-parallel spaced lines,  
       a configuration of lines that meet at one vertex,  
       a configuration of lines that meet at a plurality of vertices that define a tiling pattern,  
       a configuration of lines that meet at a plurality of vertices that fold into a polyhedron, and  
       a configuration of lines that fold into an origami figure.  
     
     
       27. The method according to  claim 26 , wherein said side walls of said recess are parallel. 
     
     
       28. The method according to  claim 26 , wherein said side walls of said recess have a divergent angle. 
     
     
       29. The method according to  claim 26 , wherein said side walls of said recess have a stepped section. 
     
     
       30. The method according to  claim 26 , wherein said recess has a generally V-shaped section. 
     
     
       31. The method according to  claim 26 , wherein said recess has a generally rectangular section. 
     
     
       32. The method according to  claim 26 , wherein said floor plane of said recess is curved. 
     
     
       33. The method according to  claim 26 , wherein said cutting device is a water jet cutter and where k equals the width of the water jet. 
     
     
       34. The method according to  claim 26 , wherein angles between two said opposing sections of said sheet metal are convex. 
     
     
       35. The method according to  claim 26 , wherein angles between two said opposing sections of said sheet metal are a combination of convex and concave angles.